Generator light

Tom Bond

Member
Noticed after done moving some snow last weekend my generator light was staying lit. Belt had about 3/4" deflection so I snugged it up some. Same thing. I checked voltage while running and it stays right at 6.3V thru the whole entire throttle range. Bad genny? VR? Whats the next best troubleshooting step? I have a spare genny that came off a 4000 4 cylinder that I think is 6V somewhere around here. Might just be easier to swap it out and see. Any ideas?
Thanks!
 
(quoted from post at 21:42:35 02/15/18) Noticed after done moving some snow last weekend my generator light was staying lit. Belt had about 3/4" deflection so I snugged it up some. Same thing. I checked voltage while running and it stays right at 6.3V thru the whole entire throttle range. Bad genny? VR? Whats the next best troubleshooting step? I have a spare genny that came off a 4000 4 cylinder that I think is 6V somewhere around here. Might just be easier to swap it out and see. Any ideas?
Thanks!
hile running, jumper BATT to ARM and see if light extinguishes and battery voltage increases. And when you post back, say what tractor you are working on.
 
Darn... Forgot that. It's on a 961. I did just jump it while running and the light did go out. I'll need to make a heavier jumper at work tomorrow as all I had was a 16ga. control jumper and it started heating up before I could measure voltage so I pulled it off. I'll check the voltage tomorrow while jumped. Thanks for your help!
 
Sorry, but I respectfully disagree with you here. You don't jump BAT to ARM, all you're doing is bypassing the cutout relay and sending
battery power straight to the armature. If the regulator is faulty and the field is not being energized normally, all you'd be doing is
powering up the armature backwards essentially. Notice the OP said his 16 gauge wire was getting hot so fast that he didn't have time to
check the voltage. That can't be right.

To troubleshoot the charging system, you need to energize the field by jumping BAT to FLD to see if the generator will put out power the
way it's designed to. If voltage increases at the armature terminal, but doesn't increase at the battery, then it's safe to assume that the
generator is working and the regulator is faulty.

To the OP: When you jump BAT to FLD, only do it long enough to observe that voltage is rising. If you leave it on, you'll eventually cook
your battery.
 
(quoted from post at 23:38:14 02/15/18) Sorry, but I respectfully disagree with you here. You don't jump BAT to ARM, all you're doing is bypassing the cutout relay and sending
battery power straight to the armature. If the regulator is faulty and the field is not being energized normally, all you'd be doing is
powering up the armature backwards essentially. Notice the OP said his 16 gauge wire was getting hot so fast that he didn't have time to
check the voltage. That can't be right.

To troubleshoot the charging system, you need to energize the field by jumping BAT to FLD to see if the generator will put out power the
way it's designed to. If voltage increases at the armature terminal, but doesn't increase at the battery, then it's safe to assume that the
generator is working and the regulator is faulty.

To the OP: When you jump BAT to FLD, only do it long enough to observe that voltage is rising. If you leave it on, you'll eventually cook
your battery.
ell, buba, you can "respectfully disagree all you want", but I have now demonstrated the the cut out was not closing. That was the first step. Next is to determine why. So do your suggestion ...next... to see if the field contacts or possibly the generator is the problem. There is NOT simply one sequence by which to trace a problem!
 
Agreed, but....if the OP had full fielded the thing from the get go, by jumping from BAT to FLD, he would have tested the generator and
regulator both at the same time, in one step. Your method bypasses the cutout relay but tells you little else. If the voltage does not rise
using your method, one still does not know whether the problem is in the regulator or the generator.

The OP stated that his 16 gauge wire started to smoke when he hooked it up, but that he didn't have time to check the voltage. For all we
know, current flow was going backwards through that wire.
 
(quoted from post at 01:51:53 02/16/18) Agreed, but....if the OP had full fielded the thing from the get go, by jumping from BAT to FLD, he would have tested the generator and
regulator both at the same time, in one step. Your method bypasses the cutout relay but tells you little else. If the voltage does not rise
using your method, one still does not know whether the problem is in the regulator or the generator.

The OP stated that his 16 gauge wire started to smoke when he hooked it up, but that he didn't have time to check the voltage. For all we
know, current flow was going backwards through that wire.
The OP stated that his 16 gauge wire started to smoke when he hooked it up, but that he didn't have time to check the voltage. For all we
know, current flow was going backwards through that wire."

AND, you only learned that (if it is in fact the case, still unknown) after he applied my suggested trouble shooting advice.
 
I fail to see the point in your last reply. If we don't know which direction current was flowing (because we don't know if it was actually charging the battery or discharging through the armature), then how is that helpful?

All your method does is bypass the cutout relay, that's it. As I suspect you already know, the function of a cutout relay to to isolate the armature from the battery when the generator is not charging to prevent the battery from discharging itself through the armature.
 
(quoted from post at 10:04:52 02/16/18) I fail to see the point in your last reply. If we don't know which direction current was flowing (because we don't know if it was actually charging the battery or discharging through the armature), then how is that helpful?

All your method does is bypass the cutout relay, that's it. As I suspect you already know, the function of a cutout relay to to isolate the armature from the battery when the generator is not charging to prevent the battery from discharging itself through the armature.

Bern, "Agreed, but....if the OP had full fielded the thing from the get go, by jumping from BAT to FLD, he would have tested the generator and
regulator both at the same time, in one step".
I don't know about 'tested', as if he does as you suggest, that big/high current that made his jumper smoke would then be trying to pass thru the closed field contacts into the armature. Those contacts are designed for about 2-4 amperes, not 50-100amperes. IF you are going to suggest applying battery voltage to the field terminal, it would be prudent to apply it to generator ONLY by disconnecting wire between field of VR and field of generator first.
 
Agreed. Note that I did not specify WHERE to do the jumping nor how exactly to do it (and neither did you by the way). I would have if I were
the initial respondent to the OP's post.

To the OP - assume I'm responding to your original post: "Disconnect the field wire at the generator, and using a jumper wire, apply battery
voltage straight to the field terminal on the generator with the engine running. Observe for a rise in voltage at the armature terminal of
the generator. If voltage rises, generator is good, and a faulty regulator or an open in the wiring is indicated. If voltage does not rise,
the generator is suspect. To further troubleshoot the generator, if the jumper wire sparked when energizing the field, that means the field
circuit in the generator is good and you most likely have worn or sticky brushes. This could well be a simple and inexpensive fix for a
person who is mechanically inclined."
 
Didn't read the previous posts, Tom, but the generator on your tractor was professionally rebuilt and does not need replacement.

IIRC, the VR was also replaced.

Check all connections.

Dean
 
I'm pretty sure my generator light issue is resolved. Remembered I had an old 6V VR from when I converted my 4000 to 12V. I threw it in and all good. Light went out when it fired up. Took the old one apart for snicks and it still looks brand new. Contacts clean. Beats me. Anyone know what the charging volts should be at the battery when running? I'm reading 6.3. Now all I have to do is figure out how to get the one VR mounting screw off the flange of the gas tank where it rolled after I set it up on top. I sure ain't pulling the tin for the screw. Maybe I'll just drive it around to shake it out! Thanks for all your help guys!
 
(quoted from post at 23:16:22 02/16/18) I'm pretty sure my generator light issue is resolved. Remembered I had an old 6V VR from when I converted my 4000 to 12V. I threw it in and all good. Light went out when it fired up. Took the old one apart for snicks and it still looks brand new. Contacts clean. Beats me. Anyone know what the charging volts should be at the battery when running? I'm reading 6.3. Now all I have to do is figure out how to get the one VR mounting screw off the flange of the gas tank where it rolled after I set it up on top. I sure ain't pulling the tin for the screw. Maybe I'll just drive it around to shake it out! Thanks for all your help guys!
ot 6.3. If able to set it, set for 7.1 to 7.3. Acceptable at 6.75 to 7.6.
 
6.3 volts is essentially static battery voltage - I'm not so sure it's really charging, regardless of what your indicator light is doing. If
it truly does not rise above 6.3 volts, you might wish to test the system as per my instructions in a prior post.

If you can get the voltage to stabilize right around 7 volts, you should be good to go.
 
Charge light went out, but the voltage is still 6.3?
How long have you ran it and how low was the battery?
What was the battery voltage with the engine off? May not
matter, but I'd be curious if it changes with run time and RPM.
 

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